This invention relates to electrical heating apparatus and more particularly to hand-held electrical heating apparatus such as soldering irons. Even more particularly, this invention relates to a holder for such soldering irons.
As integrated circuits get larger and larger, and particularly with the advent of surface mounted integrated circuits, soldering irons capable of handling these types of devices have become more sophisticated. To handle the larger, square, integrated circuits and surface mounted integrated circuits, the tips on these soldering irons have a large surface area while the barrel between the handle and the tip remains long and slender. Traditional soldering irons have a handle, a barrel to conduct heat to the tip, and a slender, pointed, tip. Using this type of iron, integrated circuits must be soldered or un-soldered one pin at a time. Irons capable of soldering large square integrated circuits and surface mounted integrated circuits must solder, or un-solder, all pins of the integrated circuit at once. To accomplish this, the tips of these irons have a surface that is similar in shape and size to the integrated circuit. Consequently, the tip is much larger than the barrel, and oftentimes even larger than the handle of the soldering iron. Also, because of the requirements for soldering surface mounted integrated circuits, and the tips have a very short lifetime.
Conventional soldering iron holders consist of a base, sometimes including the power supply for the soldering iron, and a vertical slot on top to hold the iron. With this type of holder the iron is exposed, allowing anyone near the iron to easily touch the hot iron. The exposure problem has been solved for the 15 conventional soldering iron with a shield consisting of a coil of heavy wire having a center opening into which the iron is inserted. This coil is mounted at about a 45 degree angle with respect to the base and the center opening is larger than the barrel and tip, but smaller than the handle. This allows the tip of the iron to be inserted into the coil, while the handle stays outside the coil. The iron is in such a position that it can easily be grasped in the same manner the user would grasp a pencil. The iron is typically turned on and off by a switch mounted on the base.
The large square tip of an iron for soldering surface mounted devices causes a problem with the conventional holder. Since this tip is much larger than the barrel, and often larger than the handle, the conventional wire coil holder is not satisfactory. If the center opening is large enough for the square tip, it is too large to hold the handle, and the iron falls to the bottom of the coil where it is cooled rapidly, or where it might be damaged. Also, with so large a center opening, the tip can easily touch the shield and quickly be cooled far below the desired soldering temperature, thus causing the user to have to wait for the iron to reheat each time it is to be used.
The problem of short tip life has been addressed by the device of U.S. Pat. No. 4,418,268 issued Nov. 29, 1983 to Munshaw. This device provides two vertical slots to hold a conventional soldering iron. The handle rests in a first slot, and the barrel of the iron rests in a second slot. Alongside the second slot is a detector, consisting of a light source and photocell, used to detect the presence of the iron. A circuit connected to this detector removes power from the iron when the iron has been in the holder for a predetermined period of time. This device has several disadvantages, however. First, there is no shield around the tip of the iron to prevent someone from touching the hot tip. Secondly, the iron is held in a horizontal position, and the holder contacts the handle of the iron, so it is difficult for a user to grasp the iron when it is in the holder. That is, soldering irons are most often used while being held like a pencil, so after grasping the iron while it is in the holder of the Munshaw device, a user must shift the position of the iron in their hand to a usable position, and when replacing the iron, the user must shift the iron's position again before it can be inserted back into the holder. A more convenient holder would allow a user to place and remove the iron while holding it like a pencil. Another disadvantage of the Munshaw device is that the detector is very close to the iron so it is subject to deterioration from the heat of the iron and therefore more likely to fail. Having the sensor close to the iron also requires that connecting wires be placed near the iron causing assembly problems and deterioration. Because of the way the holder of this device is constructed, if a shield were placed around the iron, the iron would be difficult to insert and remove from the holder. This problem would be exacerbated if the iron had a large square tip.
It is thus apparent that there is a need in the art for a soldering iron holder that allows an iron having a large square tip to be inserted in the holder, and provides a shield around the tip while keeping the tip from touching the shield. There is a further need in the art for such a holder that will remove power from the soldering iron after it has been in the holder for a long time, so as to preserve tip life, but which also has a long lasting sensor. A further need in the art is for such a holder that allows the soldering iron to be held in a position that is convenient for a user to grasp the iron the way they would hold a pencil. Yet another need is for such a holder that has a shield that can easily be removed for cleaning and replacement.